Electrical protective device.



B. H. SNHTH. ELECTRICAL PROTECTIVE DEVICE. APPLlCATlON FILED J-ULY 12,1915

Pafiented Dec. 3, 191.8.

Qlhhhhhk 1 77/ v 24 a [and WITNESSES I INVENTOR fi a figi w/ Baggy/)7 $77777 ATTORNEY connected transmission TJNITED STEfiiI ES 0F TURTLE CREEK, PENNSYLVANIA, ASSIGNOB TO VJESTING- HOUSE ELECTRIC AND MANUFACTURING BENJAMIN H. SMITH,

V AN IA.

COMPANY, A CORPORATION OF PENNSYL- ELECTRICAL PROTECTIVE DEVICE.

Application filed July 12, 1915.

v To all whom it may concern:

of Turtle Creek, in the county of Allegheny and State of Pennsylvania, have invented a new and .useful Improvement in Electrical Protective Devices, of which the following. is a specification.

My invention relates to electrical protec tive devices and particularly to relays.

The object of my invention is to provide a definite time-limit relay having a relatively large time element in its operation.

(lo-pending U. S. application Serial No. 771,888, filed June 5, 1913 by Almon V. Copley and Benjamin H. Smith, and assigned to the Vestinghouse Electric and Manufacturing Company, discloses a relay that is provided with a saturated transformer for the purpose of producing a definite time element in the operation of the relay. When such relays are used on ringsystems, it is advisable to have the relays so adjusted that their time elements will be materially different from each other. Heretofore it has been found ditlicult to obtain a sufficiently large range in the time element relay to permit any considerable number of such relays to be used on a single system.

provide means for materially increasing the range of the time element of definite time-limit relays.

y invention is relay, but may be adapted to other applications. It is to be understood, therefore, that the references to relays in the following description do not limit the application of the invention or restrict the scope of the claims. In the accompanying drawings, Figure 1 is a diagrammatic view of an electrical circuit to which is connected a relay embodying my invention, and Fig. 2 is a diagram illustrating the load-time curve obtained With a relay embodying my invention.

An electrical circuit 1 is provided with a circuit interrupter 2, a tripping device 3 therefor, and a time-element relay 4 that is supplied with current from a transformer 5 which is connected in the circuit 1. The relay 4 is provided for controlling the circuit of the tripping device 3 and operates in a manner hereinafter more fully set forth.

The relay 4 comprises a magnetizable core member 6 having a main winding 7, a. sec- Spceification of Letters Patent.

of this type of,

primarily intended as a Patented Dec. 3, 19?? 8. Serial No. 39,386.

ondary winding 8 and four auxiliary wind ings 9, 10, 11 and 12 disposed thereon. An armature 13 is mounted on a shaft 1 1- and is adapted to turn between a stationary magnetizable keeper or member 15 and the pole pieces 16 and 17 of the magnetizable core member 6. The armature 13 adapted to also turn between the poles of a permanent magnet 18 for the purpose of retarding its motion. A spring 19 is connected, at one end, to the shaft 1-1 and, at its other end, to a stationary member 20. A movable contact member 21 is mounted on the shaft 11, and is adapted to engage stationary contact members 22 that constitute the terminals of a circuit 23 which consists of a source of electroinotive force 24: and the winding of the tripping device 3.

he secondary winding 7 of the is connected, in series relation. to a winding 25 that is disposed on a relatively small transformer 26. the magnetizable core member of which is easily saturable. The auxiliary windings 9 and 10 are connected in parallel relation to each other, and the relay 4 circuit. thus constituted. is connected in series relation to the windings 8 and The auxiliary windings 11 and 12 are connected in parallel relation with respect to each other and in series with a winding 27 that is also disposed on the core of the transformer 26.

The windings 9 and 10 the pole pieces 16 and 17. res ectivel v. of

the magnetizable core member 6 that they exception that, in this application. the auxiliary windings 9 and 10 have been added for the purpose of opposing the effect of the windings 11 and 12. he curve a, shown in Fig. 2 of the drawings. illustrates the. time-load characteristics of the relav described in the patent application, Serial Number 771.888, and the curve 25 illustrates the time-load characteristics of a relay embodying my present invention. From the curves, it will be seen that a much greater are. so wound on transformer 26.

and 12, a current will traverse the same. It willthus be seen duces magnetic lines of force in the magnetizable core member 6 that are proportional to the value of the current traversing the circuit 1. Since the core member of the. transformer 26 is easily saturable, the windings 11 and 12 will induce a substantially constant number of magnetic lines of force in the core member 6, and the windings 9 and 10 will induce magnetic lines of force in the core member 6 that are substantially proportional to the current that traverses the circuit l and opposes the magnetic lines of force induced by the windings 11 and 12. Since the magnetic lines of force induced with each other, the armature will be cut by a substantially shifting magnetic flux that will cause the same to turn against the actionof the-spring 19. The armature 13 will develop a torque that is substantially constant, because it is developed the current traversing the circuit land the other of which is a resultant of a conjstant force and an opposing force that is proportional to the value of thecurrent traversing the circuit 1. It has been found by experiment that a very'much larger time elewhen the windings 9 and 10 are provided, and also that a very muchbetter load-time characteristic curve is obtained. The damping magnet 18 is pro vided, together with the spring 19, for the purpose of securing various time-element characteristics withinthe limits afforded by the instrument.

I have described the principle and operation of my invention, together with an ar rangement of parts which is now considered preferable, but I do not limit my invencore member having two oppositelyacting tion except as set forth in the appended claims. Y

I claim as my invention:

1. .A motor comprising a magnetizable V auxiliary windings and a main winding thereon, a relatively small magnetically saturable core member, a winding thereon a portion of the circuit of which is inductively related to the magnetizable core member and electrically-connected to one of the auxiliary windings-5 asecond winding Since the winding 27 is v connected in circuit with the windings 11' that the winding 7 inauxiliary windings and a with current that the several windings are out of phase by two forces, one of which is proportional to the value of thereon that is connected to the other auxiliary winding. v

2. A motor comprising a magnetizable core member having two oppositely-acting auxiliary windings and a main winding thereon, an armature, and means connected in circuit to cooperate with the main winding to cause the armature to developa substantially constant torque, for all values of current that traverses the main winding above a predetermined value.

3. A relay comprising a magnetizable core member having two oppositely' -acting main winding with'the said auxiliary windings thereon, one of the said auxiliary windings 5 being supplied with current in accordance ings, and means for supplylng the other auxiliary winding with a substantially constant current.

traverses the main wind-v 4. A relay comprising a magnetizable core member, a main winding thereon, two auxiliary oppositely-acting windings there on, inductively connected to the main winding, one of the said auxiliary windings being supplied with current substantially proportional to the current that traverses the main Winding, and'means for supplymg the other auxiliary windingv with a substantially constant current.

5. A relay comprising a magnetizable core member, auxiliary oppositely-acting windings thereon, an armature, and a reactor interpos e in the circuit of one of the auxiliary windings, the other auxiliary winding being sup-f I substantially in propo r plied with current tion to the current that traverses the main winding, said auxiliary windings cooperating with the main winding to cause the a main winding thereon, two

armature to develop a substantially constant torque.

6. A relay core 'memberhaving two oppositely-acting auxiliary windings, a main winding and a secondary winding'thereon, an armature, and a transformer having two windings thereon, one of the transformer windings being connected in circuit-with one of the auxiliary windings and theother being connected in circuit with the secondary winding and with the other auxiliary winding, said transformerbeing adapted to-be magnetically saturated under predetermined conditions.

7. A relay comprising an' armature, two

oppositely-acting auxiliary windings, a mam winding and-a transformer interposed between the main winding and one of the auxiliary windings and adapted to be .mag-

netically saturated under predetermined conditions, the other auxiliary winding being supplied current that traverses the main winding.

comprising a magnetizable with current in accordance with the 5 saturated transformer having 8. A relay comprising an armature, a magnetizable core member having two oppositelyacting auxiliary windings and a main winding thereon, and a normally magnetically a winding inductively connected to the magnetizable core member and electrically connected to one winding that is I sub 191 the auxiliary windings and a second connected to the other auX- ry winding.

n testimony whereof I have hereunto scribed my name this 29th day of June, 5.

BENJAMIN H. SMITH. 

